Carboxylic acids are notoriously difficult substrates for direct hydrogenation to the corresponding alcohols using heterogeneous hydrogenation catalysts. Standard metals (e.g. Pt, Pd, Ni) used in hydrogenation catalysts are relatively inactive for hydrogenation of carboxylic acids or else require very high temperatures and pressures. Ruthenium has been known for some time to have reasonable activity for the hydrogenation of carboxylic acids to the corresponding alcohols. However, observed hydrogenation rates are still very slow, especially compared to other carbonyl-containing species such as ketones and aldehydes. There is interest in developing new catalysts that are faster and more effective than ruthenium alone for carboxylic acid hydrogenation at mild conditions to form the corresponding alcohol.